Side Glass Weatherstripping

Hi Everyone,
I am replacing all of the glass in my 1969 Dodge Dart two door and I am hoping someone can answer a question about the side glass windows. There is a metal strip on the front side glass that butts up against the rear quarter glass. Inside that metal strip there was a seal of some kind. On my car it was so old and brittle I had to like cut it out with a razor knife (total pain in the @ss). Anyway, does anyone know what that seal is called or where I can buy replacements. Thanks in advance.

Louis